WC-Co-Re Cemented Carbides- Structure, Properties and Potential

International Journal of Refractory Metals & Hard Materials 78 (2019) 247–253

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WC-Co-Re cemented carbides: Structure, properties and potential applications T ⁎ I. Konyashina,b, , S. Faraga, B. Riesa, B. Roebuckc a Element Six GmbH, Burghaun D-36151, Germany b National University of Science and Technology MISiS, Moscow 119049, Russia c National Physical Laboratory, Teddington TW11 0LW, United Kingdom

ARTICLE INFO ABSTRACT

Keywords: Cemented carbides of the WC-Co-Re system represent a new class of hard materials having a significantly in- Cemented carbides creased Young's modulus, hot hardness and high temperature creep resistance. The WC-Co-Re phase diagram Co-Re binders was evaluated and compared with the corresponding WC-Co phase diagram. Physical and mechanical properties Microstructure of such composites were measured at room and elevated temperatures and compared with those of conventional High-temperature properties WC-Co cemented carbides. Microstructures of the WC-Co-Re cemented carbides at different carbon contents, binder contents and WC grain sizes were examined. Rhenium being dissolved in the Co-based binder is found to be a very strong grain growth inhibitor with respect to WC coarsening during liquid-phase sintering. The Young's modulus, hot hardness and high temperature creep resistance of the WC-Co-Re cemented carbides are greater than those of conventional WC-Co cemented carbides. Due to their unique properties the WC-Co-Re materials can find applications in use in high-pressure high-temperature components for synthesis of diamond and c-BN and cutting Ni-based super alloys and other heat-generating workpiece materials.

1. Introduction resistance of the composite materials, which in turn is dependent on its Young's modulus and high-temperature creep resistance. It is well known that high-pressure high-temperature (HPHT) It is well understood that additions of Re to binders of WC-based components such as anvils and dies employed for the synthesis of dia- cemented carbides allows improvement of their high-temperature mond, polycrystalline diamond (PCD) or cubic boron nitride (c-BN) are properties [4–10]. subjected to harsh operation conditions. They include ultra-high pres- Cemented carbides containing rhenium were first patented in 1949 sures (above 5 GPa) and relatively high temperatures (of above [3]; however, at this time no information regarding potential ad- 1400 °C). Presently, there is a general trend to fabricate diamond and c- vantages of partial substitution of Co by Re in the cemented carbide BN by so-called direct conversion, which enables the synthesis of dia- binder for high temperature applications was available. mond or c-BN out of graphite or hexagonal boron nitride without em- WC-Co-Re cemented carbides characterized by particular Re to Co ploying catalysts [1,2]. As a result, nano-structured diamonds and c-BN ratios were developed for fabricating cutting tools in the Soviet Union with exceptionally high hardness values can be obtained. However, [4–8]. Although, it was established that such cemented carbides are direct conversion is only achievable at extremely higher pressures ex- characterized by significantly higher hot hardness and improved per- ceeding 12 GPa. Such unfavorable conditions inevitably lead to the formance at elevated temperatures in comparison with conventional deformation of HPHT components and, if the deformation exceeds a WC-Co materials, such composites were not applied in HPHT applica- certain level, the components fail. Currently, the large-scale fabrication tions. of superhard materials at pressures above 12 GPa is limited by rela- Cemented carbides containing Co-Re binders and mixed (W,Re)C tively short lives of HPHT components made of conventional WC-Co carbides were examined in refs. [9, 10]. It was found that rhenium materials. Therefore, the development and research of novel cemented added to the Co-based binder phase forms a solid solution with cobalt carbides with improved high temperature properties currently can be decreasing the stacking fault energy of the binder phase, which leads to considered as a topic of great interest. Prolonging the lifetime of HPHT the stabilization of the hcp Co modification. Tungsten and rhenium components can generally be achieved by improving the deformation were found to form mixed carbides having different compositions.

⁎ Corresponding author at: Element Six GmbH, Burghaun D-36151, Germany. E-mail address: [email protected] (I. Konyashin). https://doi.org/10.1016/j.ijrmhm.2018.10.001 Received 24 July 2018; Received in revised form 12 September 2018; Accepted 3 October 2018 Available online 05 October 2018 0263-4368/ © 2018 Elsevier Ltd. All rights reserved. I. Konyashin et al. International Journal of Refractory Metals & Hard Materials 78 (2019) 247–253

Waldorf et al. examined the performance of WC-Co-Re cemented carbides in machining Ni-based superalloys and established that their tool lifetime is prolonged by up to 150% in comparison with conventional WC-Co carbide grades [11]. The major objective of this work was to optimize fabrication conditions of WC-Co-Re cemented carbides, produce such cemented carbides with diﬀerent compositions and WC mean grain sizes, and ex- amine their physical and mechanical properties at room temperature and elevated temperatures.

2. Experimental procedure

A number of laboratory batches of WC-Co-Re cemented carbides with different carbon contents, WC mean grain sizes, binder contents and ratios between Re and Co were produced and examined. WC powders with mean grain sizes of 3 μm and 0.8 μm, a Co powder with a grain size of about 1 μm and a Re powder with a grain size of 1–3 μm were milled in hexane with different amounts of carbon black and 1.8% paraffin wax by use of attritor-mills and ball-mills. The batches produced from the medium-coarse WC powder with a mean particle size of 1.7 μm were designated as “medium-grain cemented carbides” and Fig. 1. Vertical sections of the W-Co-Re-C phase diagram (red lines) at 9 wt% those obtained from the fine-grain WC powder with a particle size of Re + 6 wt% Co in comparison with the W-Co-C phase diagram at 10 wt% Co 0.6 μm were designated as “submicron cemented carbides”. After (black lines). The WC-Co diagram is redrawn from Ref. [13]. (For interpretation of the references to color in this figure legend, the reader is referred to the web drying a slurry obtained in such a way, carbide samples were pressed version of this article.) and sintered in a laboratory Sinter-HIP furnace at a temperature of 1520 °C for 1 h followed by cooling at rates varying from 0.5 degrees/ min to 4 degrees/min. The Vickers hardness was measured according to above approx. 1430 °C. This means that if the WC-Co-Re cemented the ISO 3878 standard at a load of 300 N. The transverse rupture carbides with medium-low and low carbon contents are fast cooled η strength (TRS) was measured according to the ISO 3327 standard. The from sintering temperatures, they could contain -phase, which did not compression strength was measured according to the ISO 4506 standard decompose to the thermodynamically stable mixture of WC + Co/Re. at room and elevated temperatures. The hot hardness and length of the Therefore, after sintering WC-Co-Re cemented carbides have to be Palmqvist cracks were measured at a load of 300 N at temperatures of cooled down at relatively low rates to ensure a full decomposition of the η 300 °C, 500 °C and 800 °C in an Ar atmosphere. The Young's modulus -phase, which co-exists with WC and liquid phase at temperatures of was measured with the aid of the ultrasonic method by means of above 1420 °C. This is illustrated in Fig.2, which shows that the mi- measuring the transverse and longitudinal components of the speed of crostructure of the WC-Co-Re batch with a medium-low carbon content η η sound through the material. The high temperature creep resistance was comprises inclusions of -phase after fast cooling and is free of -phase examined at a temperature of 800 °C according to the procedure de- as a result of slow cooling. scribed in Ref. [12]. The XRD measurements were carried out on a The special features of the W-Co-Re-C phase diagram and the pre- Bruker D8 Advance instrument using a Co anode. sence of large amounts of Re dissolved in the binder of WC-Co-Re cemented carbides lead to some peculiarities of their microstructure and 3. Results and discussion properties. Figs. 3 and 4 show the typical microstructure of the medium-grain Fig. 1 schematically shows the W-Co-Re-C phase diagram at 9 wt% WC-Co-Re cemented carbide in comparison with that of a conventional Re + 6 wt% Co, which was elaborated based on the results obtained in WC-Co material obtained from the same grade of WC powder. As one the literature (Ref. [6]) and experimental results of the present work, in can see in Fig.3, the microstructure of the WC-Co-Re cemented carbide fi fi comparison with the corresponding WC-Co diagram at 10 wt% Co re- is signi cantly ner than that of the conventional WC-Co cemented drawn from Ref. [13]. When taking into account that Re has a sig- carbide. Therefore, Re acts as a strong WC grain growth inhibitor nificantly higher density than Co, the WC-Co Re cemented carbide with suppressing the WC coarsening process. According to the results of Ref. the binder containing 9 wt% Re and 6 wt% Co is characterized by nearly [14] Re segregates at WC/binder grain boundaries of WC-Co-Re ce- the same percentage of the binder phase by volume in comparison with mented carbides. It can therefore be supposed that the phenomenon of a WC-Co material containing 10 wt% Co. suppressing the WC grain growth in WC-Co-Re materials is similar to ff It can be seen in Fig. 1 that the W-Co-Re-C phase diagram differs the well-known inhibition e ect of conventional grain growth in- from the W-Co-C phase diagram. The following special features of the hibitors segregating at WC-Co grain boundaries [15,16]. ff W-Co-Re-C phase diagram should be mentioned. The grain growth inhibiting e ect of Re is quite important with First, all the melting points in the W-Co-Re-C diagram are shifted respect to fabricating submicron cemented carbides usually employed towards higher temperatures. Therefore, WC-Co-Re cemented carbides for HPHT components, as there is no need for adding conventional fi have to be sintered at significantly higher temperatures in comparison grain growth inhibitors to the ne- grained WC-Co-Re cemented car- with conventional WC-Co materials. bides. Figs. 4 and 5 show microstructures of the submicron WC-Co-Re Second, to the two-phase region not comprising η-phase and free cemented carbide not containing grain growth inhibitors, which are fi carbon for WC-Co-Re cemented carbides is slightly shifted towards quite ne and uniform, and do not comprise abnormally large WC higher carbon contents. The shift is relatively insignificant, but still grains. Note that this cemented carbide was sintered at a temperature of should be taken into account when fabricating the WC-Co-Re cemented 1520 °C, which is noticeably higher than temperatures usually em- carbides. Note that the width of the two-phase region in the W-Co-Re-C ployed for sintering submicron WC-Co grades. phase diagram is close to that in the W-Co-C phase diagram. Another unusual microstructural feature can be observed when fast η Third, additions of Re to the binder noticeably broaden the region, cooling WC-Co-Re composites at medium-low carbon contents. The - where WC + η-phase + liquid are in equilibrium at temperatures of phase inclusions that formed as a result of fast cooling after sintering

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mixed (W,Re)C carbides according to Ref. [10]. Nevertheless, the exact composition and stoichiometry of the η-phases forming in the WC-Co- Re cemented carbides are subjects of a separate study. Results XRD analysis of the WC-Co-Re cemented carbide shown in Fig. 7 indicate the absence of fcc Co. The peaks corresponding to the binder phase lie between those of hcp-Co and hcp-Re. Thus, it can be assumed that the binder consists of a Co-Re solid solution having a hexagonal crystal lattice, as Co and Re are known to form an unin- terrupted series of solid solutions. Large amounts of Re dissolved in the Co-based binder of WC-Co-Re cemented carbides have a strong influence of their magnetic properties. Fig. 8 indicates the dependence of the coercive force and the magnetic moment on the carbon content in the WC-Co-Re cemented carbides. Both the coercivity and the magnetic moment are almost independent on the carbon content unlike conventional WC-Co materials, which makes it difficult to determine the phase composition and WC mean grain size of WC-Co-Re cemented carbides based on their magnetic properties. WC-Co-Re cemented carbides are characterized by a high combination of hardness, fracture toughness and TRS at room temperature, which is comparable with that of conventional WC-Co cemented carbides. As it can be seen in Fig. 9, a point indicating the combination of hardness and fracture toughness of the medium-grain carbide grade containing 9 wt% Re + 6 wt% Co lies on the baseline for conventional WC-Co cemented carbides. Its TRS (2920 MPa) is also comparable with that of a medium-coarse WC-Co mining grade with 10 wt% Co (2800 MPa, see Ref. [18]). It was found that the WC-Co-Re cemented carbides have sig- Fig. 2. Microstructures of the medium-grain WC-Co-Re cemented carbides nificantly improved physico-mechanical properties at elevated tem- containing 9 wt% Re + 6 wt% Co with the total carbon content of 5.45 wt% peratures. The curves shown in Fig. 10 provide evidence that the cooled at different rates from the sintering temperature (1520 °C) down to hardness reduction as a function of temperature (20–800 °C) of the WC- 1300 °C: a – cooling rate of 4 degrees per minute and b – cooling rate of 0.5 Co-Re material is less significant than that for conventional WC-Co degrees per minute (light microscopy after etching in the Murakami reagent). cemented carbides. The hardness reduction of the WC-Co-Re cemented carbide is nearly two times smaller in comparison with the conven- are not fully etched by the Murakami reagent and exhibit a brown color tional WC-Co material at temperatures of 300 °C and 500 °C, which are after long etching (Fig. 6). As Co and Re form a solid solution as well as typical for the operation of HPHT components. The improved hot Re and W form mixed (W,Re)C carbides [11], not only the binder but hardness is thought to be decisive for the fabrication of machining tools also inclusions of the η-phase will comprise Re (see EDX measurements for Ni-super alloys or other heat generating materials that require a in Fig. 6a), resulting in an improved corrosion resistance of both phases high degree of thermal and mechanical stability of cutting edges. in different aggressive media including the Murakami reagent. It was Results on the compression strength, which plays an important role clearly established that the large inclusions shown in Fig. 6a comprise when operating HPHT components, of the submicron WC-Co-Re ce- just the η-phase, as they become dark after etching in the Murakami mented carbide and conventional WC-Co material shown in Fig. 11 reagent for 5 min. Numerous EDX measurements of different large in- indicate that the difference in the compression strength values is mar- clusions of the η-phase in the WC-Co-Re samples indicated that they ginal. contain roughly 40 to 50 at.% Co, 10 to 20 at,% W and 30 to 40 at.% Re. Fig. 12 shows the temperature dependence of the Palmqvist crack

Based on these results it can be supposed that the η1-phase is present in lengths for the submicron WC-Co-Re cemented carbide. It can be seen the samples with the approximate composition of Co3(W,Re)3C, so that that the WC-Co-Re carbide is characterized by only slightly longer tungsten atoms in the η-phase are partially substituted by Re atoms. Palmqvist cracks at elevated temperatures compared to room tem- This can be expected when taking into account that both W and Re form perature. The Palmqvist crack measurement is thought to be inﬂuenced by the elasto-plastic behavior of the WC-Co-Re cemented carbides,

Fig. 3. Microstructures of the medium-grain WC-10%Co cemented carbide (left) and medium-grain WC-Co-Re cemented carbide containing 9 wt% Re + 6 wt% Co (right). Sintering at 1520 °C followed by slow cooling down to 1250 °C. (light microcopy after etching in the Murakami reagent).

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Fig. 4. Microstructure of the medium-grain WC-Co-Re cemented carbide containing 9 wt% Re + 6 wt% Co (left) and the submicron WC-Co-Re cemented carbide containing 5.5 wt% Re + 3.7 wt% Co (right) (EBSD).

Fig. 5. Microstructure of the submicron WC-Co-Re cemented carbide containing 5.5 wt% Re + 3.7 wt% Co (light microcopy after etching in the Murakami reagent. resulting in shorter cracks when increasing temperature; this phenomenon is also observed in WC-Co cemented carbides. One of the most important parameters affecting the performance of HPHT components is Young's modulus of cemented carbides indicating their stiffness. As shown in Fig. 13, the Young's modulus of the WC-Co- Re materials increases as a result of the partial substitution of Co by Re, while keeping the volume percentage of the binder constant. When taking into account the noticeably higher hot hardness of WC- Co-Re cemented carbides in comparison with conventional WC-Co materials mentioned above it can be supposed that the Re-containing cemented carbides are characterized by improved high temperature creep resistance. Indeed, as it can be seen in Fig. 14 the same values of Fig. 6. Microstructure of the WC-Co-Re cemented carbide (13.5 wt% Re + 9 wt compression strain rates are obtained for WC-Co-Re cemented carbides % Co) containing inclusions of η-phase at a low carbon content: a– HRSEM at noticeably higher loads than for the conventional WC-Co material, image indicating a Co pool comprising round inclusions of η-phase and the indicating that the Co-Re binders have a significantly improved high- corresponding Re:Co ratios (at.%) obtained by EDX, and b - light microscopy temperature creep resistance. image with inclusions of η-phase (marked by arrows) having a yellow-brown In spite of high prices of Re powders and consequently higher color after etching in the Murakami reagent for 5 min. (For interpretation of the production costs of the WC-Co-Re cemented carbides they can find references to color in this figure legend, the reader is referred to the web ver- applications in fields, where their unique high temperature properties, sion of this article.) namely significantly improved creep resistance, increased and hot hardness, play a decisive role. These are primarily HPHT components re-used many times. Thus, when taking into account the high price of for diamond and c-BN synthesis and cutting tools for machining su- Re, only an initial large investment is needed for the fabrication of peralloys and other heat-generating workpiece materials. HPHT components made of WC-Co-Re cemented carbides, which is In HPHT applications, the increased Young's modulus of the WC-Co- thought to make their employment in the field of diamond and c-BN Re cemented carbides should also play an important role. It is well synthesis feasible. It is expected that using WC-Co-Re cemented car- known that HPHT components are completely recycled after operation. bides in HPHT components operating at extremely high pressures of the It was reported in ref. [19] that WC-Co-Re cemented carbides can be order of 15 GPa needed for obtaining diamond and c-BN by direct recycled in a similar way as conventional WC-Co materials, therefore, conversion without employing catalysts might be essential. Re contained in the WC-Co-Re cemented carbides can be recycled and It should be noted that the Re to Co ratio of 60 wt% Re to 40 wt% Co

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Fig. 7. Diﬀraction pattern of the WC-9wt%Co-13.5wt%Re cemented carbide.

Fig. 9. The combination of hardness and fracture toughness of the WC-Co-Re cemented carbide (9 wt% Re + 6 wt% Co) in comparison with the baseline for conventional WC-Co cemented carbides according to ref. [17].

Fig. 8. Dependencies of a – magnetic coercivity and b - magnetic moment on the carbon content for the medium-grain WC-Co-Re cemented carbide containing 9 wt% Re and 6 wt% Co. was mainly used in this study based on the results of Refs. [7, 8], in Fig. 10. Hardness reduction as a function of temperature of sub-micron WC-Co- which diﬀerent compositions of the binder phase (the Re to Co ratios) Re cemented carbide containing 5.5 wt% Co and 3.7 wt% Re in comparison were examined. In particular, in Refs. [7, 8] it was established that at with conventional submicron cemented carbide with 6 wt% Co. the Re to Co ratio of 60:40 the binder comprises only the hcp phase and

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Fig. 11. Compression strength of the ultrafine WC-Co Re cemented carbide containing 5.5 wt% Co and 3.7 wt% Re in comparison with the conventional Fig. 14. Dependences of strain rates for the WC-Co-Re and WC-Co cemented submicron grade with 6 wt% Co at room temperature and elevated tempera- carbides on the compression stress at a temperature of 800 °C. tures. grain boundaries [14]. The W solubility in the binder is not significantly influenced by Re additions, as the tungsten content measured in large Co-Re pools by EDX was found to be about 5 to 10 at.% at low carbon contents. This tungsten content is close to that in WC-Co cemented carbides with low carbon contents, so that the impact of carbon activity on the tungsten solubility in the Co-Re binders appears not to be significant. It should be noted that another addition to WC-Co cemented carbides is known to be ruthenium (see e.g. [20,21]). The hardness of WC- Co materials with Ru additions is found to increase and toughness is found to decrease when increasing the ruthenium content leading to improved abrasion resistance of cemented carbides containing Ru. Nevertheless, there is no information in the literature on high temperature properties of cemented carbides containing Ru additions, so that it is not possible to evaluate whether additions of Ru would be useful for fabricating HPHT components. Also, it was established in Ref. fi Fig. 12. Temperature dependence of the Palmqvist cracks' length for the sub- [20] that adding even relatively insigni cant amounts of Ru (3 wt% Ru micron WC-Co-Re cemented carbide containing 5.5 wt% Co and 3.7 wt% Re. to WC-10 wt% Co) resulted in a noticeable decrease of fracture toughness (up to 30%). Therefore, mechanical properties of cemented carbides containing Ru at room temperature appear to be inferior in comparison with those of cemented carbides containing large additions of Re. It is well known that cutting tools for machining superalloys and other heat-generating workpiece materials are subjected to extremely high cutting temperatures [11]. When taking into account the significantly increased hot hardness of WC-Co-Re carbide grades, they can be effectively employed in machining Ni- and Co-based superalloys, which was established in Refs. [7, 11]. Another advantage of WC-Co-Re cemented carbides in this application is the possibility of their fabrication as submicron and ultra-fine grades without employing conventional WC grain growth inhibitors, as Re acts as a very strong grain growth inhibitor, which ensures obtaining cutting inserts with extremely fine and uniform microstructure.

Fig. 13. Young's modulus of WC-Co-Re cemented carbides as a function of the 4. Conclusions Re percentage in the binder phase. 1. The W-Co-Re-C phase diagram noticeably differs from the W-Co-C phase diagram, which requires the need for the elaboration and the corresponding WC-Co-Re cemented carbides are characterized by optimization of special fabrication conditions for obtaining WC-Co- the best combination of high-temperature TRS, hot hardness and per- Re cemented carbides with suitable microstructure and properties. formance in metal-cutting. The high Re additions of 60 wt% was found 2. Rhenium acts as a strong WC grain growth inhibitor suppressing the to be mandatory for the optimized high-temperature properties and WC coarsening process, so that no additions of conventional grain performance in metal cutting. At lower Re to Co ratios the martensitic growth inhibitors are needed in the fabrication of submicron WC- fcc to hcp transformation also occurs, but its rate is significantly lower. Co-Re grades with fine and uniform microstructure. A solid-solution hardening effect is thought to be the major mechanism 3. The Young's modulus, hot hardness and high-temperature creep explaining the established improved high-temperature creep resistance. resistance of the WC-Co-Re cemented carbides are noticeably The other mechanism can be the suppression of grain boundaries' greater than those of conventional WC-Co cemented carbides. sliding at elevated temperatures, as Re is known to segregate at WC/Co

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4. Potential applications of the WC-Co-Re cemented carbides are re- [9] A.F. Lisovsky, N.V. Tkachenko, V. Kebko, Structure of a binding phase in Re-alloyed lated to their significantly improved high-temperatures properties. WC-Co cemented carbides, Int. J. Refractory Met. Hard Mater. 10 (1991) 33–36. [10] R.F. Havell, Y. Baskin, Rhenium-carbon-tungsten interactions, J. Electrochem. Soc. Therefore, the cemented carbides with Co-Re binders can arguably (108) (1961) 1068–1069. be employed for HPHT components for diamond and c-BN synthesis, [11] D. Waldorf, M. Stender, S. Liu, D. Norgan, Alternative Binder Carbide Tools for and cutting tools for machining superalloys and other heat-gen- Machining Superalloys, Proceedings of the International Conference on Manufacturing Science and Engineering, October 7–10, Evanston, Illinois, USA, erating workpiece materials. 2008, pp. 1–9. [12] B. Roebuck, S. Moseley, Tensile and compressive asymmetry in creep and mono- Acknowledgment tonic deformation of WC/Co hardmetals at high temperature, Int. J. Refract. Met. Hard Mater. 48 (2015) 126–133. [13] A. Petersson, Cemented carbide Sintering: Constitutive Relations and This work was financially supported by the European Union's Microstructural Evolution, Royal Institute of Technology, Sweden, Stockholm, 2004 Horizon 2020 Research and Innovation Programme under the Ph.D thesis. Flintstone2020 project (Grant Agreement No. 689279). [14] Yamaguchi Ryosuke, Okada Kazuki, Daito Masanori, Akiyama Kazuhiro, Cutting Tool Made from WC Based Cemented Carbide and Cutting Tool Made from Surface Coating WC Based Cemented Carbide which Exhibit Excellent Chipping Resistance References in Cutting Work of Heat Resistant Alloy, JP2011–235410, (2011). [15] S. Lay, S. Hamar-Thibault, A. Lackner, Location of VC in VC, Cr3C2 codoped WC-Co cermets by HRTEM and EELS, Int. J. Refract. Met. Hard Mater. 20 (2002) 61–69. [1] T. Irifune, et al., Ultrahard polycrystalline diamond from graphite, Nature 421 [16] Xingwei Liu, Xiaoyan Song, Haibin Wang, Xuemei Liu, Fawei Tang, Hao Lu, (2003) 599. Complexions in WC-Co cemented carbides, Acta Mater. 149 (2018) 164–178. [2] N. Dubrovinskaya, et al., Superhard nanocomposite of dense polymorph of boron [17] B. Roebuck, M.G. Gee, R. Morrell, Hardmetals – microstructural design, testing and nitride: noncarbon material has reached diamond hardness, Appl. Phys. Let. 90 property maps, in: G. Kneringer, P. Rödhammer, H. Wildner (Eds.), Proceedings of (2007) 101912. the 15th International Plansee Seminar, vol. 4, Plansee Group Reutte, Austria, 2001, [3] Mallory Metallurgical Products LTD, UK patent 622041, (1949). pp. 245–266. [4] I.N. Chaporova, V. Kudryavtzeva, Z. Sapronova, Sintered Cemented Carbide, [18] I. Konyashin, Cemented carbides for mining, construction and wear parts, in: SU616814, (1975). V. Sarin (Ed.), Comprehensive Hard Materials, Elsevier Science and Technology, [5] Z. Sapronova, K. Chernjavskij, V. Zanozin, et al., Burden for Obtaining Sintered 2014Editor-in-Chief. Hard Alloys, SU1783853, (1990). [19] I. Konyashin, B. Ries, Cemented Carbide Material and Method of Making Same, PCT [6] I.N. Chaporova, Z.N. Sapronova, Investigation of the W-C-Re-Co System, Theory Patent Applications, (2014) (WO2014/122306A2). – and Practice of Cemented Carbide Application, Moscow, 1991, pp. 12 15. [20] T.L. Shing, S. Luyckx, I.T. Northrop, I. Wolff, The effect of ruthenium additions on [7] I.N. Chaporova, Z.N. Sapronova, et al., Mechanical and Performance Properties of hardness, toughness and grain size of WC-Co, Int. J. Refractory Met. Hard Mater. 19 the WC-Re-Co Cemented Carbides, Properties and Application of Cemented (2001) 41–44. – Carbides, Moscow, 1991, pp. 30 34. [21] J.H. Potgieter, N. Thanjekwayo, P. Olubambi, et al., Influence of Ru additions on [8] I.N. Chaporova, V.N. Kudryavtzeva, Z.N. Sapronova, Investigation of Structure and the corrosion behaviour of WC–Co cemented carbide alloys in sulphuric acid, Int. J. ff Properties of Alloys of the W-C-Re-Co System, Quality and E ectiveness of Refractory Met. Hard Mater. 29 (2011) 478–487. Cemented Carbide Application, Moscow, 1984, pp. 7–9.

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